Understanding Inconsistent Step-Length Asymmetries Across Hemiplegic Stroke Patients

Roerdink, Melvyn; Beek, Peter J.

doi:10.1177/1545968310380687

Cited by 85 publications

(103 citation statements)

References 20 publications

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“…However, our results show few differences in stepping patterns according to turn direction; a finding that has also been reported in previous studies [5][6][7]. Given that the direction and extent of step asymmetry has been shown to vary according to age, motor recovery level and walking speed [26][27][28], systematic differences in stepping patterns according to the direction of the turn may be obscured by the complexity of relationships between these variables. This is the first report of turning under dual task conditions and so opportunities for like-for-like comparisons with other studies are limited.…”

Section: Discussionsupporting

confidence: 88%

Effects of dual task on turning ability in stroke survivors and older adults

2014

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Section: Discussionsupporting

confidence: 88%

Effects of dual task on turning ability in stroke survivors and older adults

2014

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“…As several biomechanical factors could affect the forward propulsion, the authors quantified the joint moment impulses of the hip, knee, and ankle during late single stance phase and double support phase. Briefly, their results showed that all groups (longer paretic, shorter paretic and equal step length) presented a reduced plantarflexion moment impulse in late single stance and double support phases, which is coherent with the reduced trunk progression during the non-paretic step (when the paretic foot propulses) previously found by Roerdink et al [26]. However, in individuals with longer paretic step, this observed reduction in plantarflexion moment impulse was more important [17].…”

Section: Biomechanical Impairments Underlying Spatial Asymmetrysupporting

confidence: 64%

“…This quantification allows inter-individual, intersegmental, and inter-parameter comparisons. Among various possibilities of SI [14,17,[25][26][27][28][29], current examples are: A value of 0% represents perfect symmetry for these indices except for the second SI sum equation for which a value of 50% represents perfect symmetry. Limitations of some symmetry indices were analyzed in a study by Zifchock et al [24].…”

Section: Symmetry Indices (Si)mentioning

confidence: 99%

“…Indeed, among individuals with step length asymmetry, 47% to 76% present a longer step on the paretic side [14,27]. In order to better understand the variability of step length asymmetry, a group of researchers [26] suggested dividing step length into two spatial components, which are the trunk progression (TP) during step and the forward foot placement (FFP) relative to the trunk at heel-strike [26]. This analysis of the step length relative to these two components is very interesting because each component could be explained by specific biomechanical impairments.…”

Section: Spatiotemporal Asymmetries and Their Relationshipsmentioning

confidence: 99%

“…However, the direction of asymmetry in FFP varied in direction among the individuals. Furthermore, step length asymmetry was determined by the sum of the asymmetries in these two components [26]. Reporting these spatial parameters in future studies will certainly help to better explain the biomechanical compensatory strategies that lead to step length asymmetry in individuals post stroke.…”

Section: Spatiotemporal Asymmetries and Their Relationshipsmentioning

confidence: 99%

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Understanding Spatial and Temporal Gait Asymmetries in Individuals Post Stroke

Lauzière¹,

Betschart²,

Aïssaoui³

et al. 2014

Int J Phys Med Rehabil

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Gait asymmetry in spatial and temporal parameters and its impacts on functional activities have always raised many interesting questions in research and rehabilitation. The aim of this topical review is threefold: 1) to examine different equations of asymmetry of gait parameters and make recommendations for standardization, 2) to deepen the understanding of the relationships between sensorimotor deficits, spatiotemporal (step length, swing time and double support time) and biomechanical (kinematic, kinetic, muscular activity) parameter asymmetries during gait and, 3) to summarize the impacts of gait asymmetry on walking speed, falls, and energy cost in individuals post stroke. In light of current literature, we recommend quantifying spatiotemporal asymmetries by calculating symmetry ratios. However, for other gait parameters (such as kinetic or kinematic data), the choice will depend on the variability of the data and the objective of the study. Regardless of the selected asymmetry equation, we recommend presenting the asymmetry values in combination with the mean value of each side to facilitate comparisons between studies. This review also revealed that sensorimotor deficits clinically measured are not sufficient to explain the large variability of spatiotemporal asymmetries (particularly for step length and double support time) in individuals post stroke. Biomechanical analysis has been identified as a relevant approach to understanding gait deviations. Studies that linked biomechanical impairments to spatiotemporal asymmetries suggest that a balance issue and an impaired paretic forward propulsion could be among the important factors underlying spatiotemporal asymmetries. In our opinion, this paper provides meaningful information to aid in better understanding gait deviations in persons after stroke and establishes the need for future studies regrouping individuals post stroke according to their spatiotemporal asymmetries. Furthermore, further studies targeting efficacy of locomotor rehabilitation and the impacts of gait asymmetry on risk of falls and energy expenditure are needed.

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By counteracting gravity, triceps surae sets both kinematics and kinetics of gait

et al. 2014

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In the single‐stance phase of gait, gravity acting on the center of mass (CoM) causes a disequilibrium torque, which generates propulsive force. Triceps surae activity resists gravity by restraining forward tibial rotation thereby tuning CoM momentum. We hypothesized that time and amplitude modulation of triceps surae activity determines the kinematics (step length and cadence) and kinetics of gait. Nineteen young subjects participated in two experiments. In the gait initiation (GI) protocol, subjects deliberately initiated walking at different velocities for the same step length. In the balance‐recovery (BR) protocol, subjects executed steps of different length after being unexpectedly released from an inclined posture. Ground reaction force was recorded by a large force platform and electromyography of soleus, gastrocnemius medialis and lateralis, and tibialis anterior muscles was collected by wireless surface electrodes. In both protocols, the duration of triceps activity was highly correlated with single‐stance duration (GI, R2 = 0.68; BR, R2 = 0.91). In turn, step length was highly correlated with single‐stance duration (BR, R2 = 0.70). Control of CoM momentum was obtained by decelerating the CoM fall via modulation of amplitude of triceps activity. By modulation of triceps activity, the central nervous system (CNS) varied the position of CoM with respect to the center of pressure (CoP). The CoM‐CoP gap in the sagittal plane was determinant for setting the disequilibrium torque and thus walking velocity. Thus, by controlling the gap, CNS‐modified walking velocity (GI, R2 = 0.86; BR, R2 = 0.92). This study is the first to highlight that by merely counteracting gravity, triceps activity sets the kinematics and kinetics of gait. It also provides evidence that the surge in triceps activity during fast walking is due to the increased requirement of braking the fall of CoM in late stance in order to perform a smoother step‐to‐step transition.

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Understanding Inconsistent Step-Length Asymmetries Across Hemiplegic Stroke Patients

Cited by 85 publications

References 20 publications

Effects of dual task on turning ability in stroke survivors and older adults

Effects of dual task on turning ability in stroke survivors and older adults

Understanding Spatial and Temporal Gait Asymmetries in Individuals Post Stroke

By counteracting gravity, triceps surae sets both kinematics and kinetics of gait

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